Laminated paperboard sheet material



V. A. ROSS LAMINATED PAPERBOARD SHEET MATERIAL July zo, 1954 ZU?? 07.' e 055, @XM A 5677@ J5 Patented July 20, 1954 LAMINATED PAPERBOARD SHEET MATERIAL Valentine A. Ross, Wilmette, Ill., assgnor to Chicago Cardboard Company, a corporation of Illinois Application June 30, 1950, Serial No. 171,416

Claims.

This invention relates to a decorative laminated paperboard sheet material, and in particular it relates to such :a material which is so treated as to be substantially free from any tendency to warp in any direction, so that it may be used as a floor covering. Its surfaces may be lithographed or otherwise decorated so that it may be used for advertising purposes.

One of the principal problems in the production of inexpensive and attractive paperboard display devices is that the paperboard ordinarily Warps and distorts, so that such a device needs a frame or other stiffening means if it is to be hung on a wall; and it has been impossible to use paperboard :as a floor covering because of its warping tendency. Insofar 4as applicant is aware nobody has heretofore produced a laminated paperboard sheet which is devoid of any substantial, or injurious, tendency to warp or curl.

The paperboard product of this invention is very useful :as a iloor covering, as in a, kitchen,

or for an automobile floor mat, or to make floor mats bearing advertising display material, because it will lie hat without Iany frame or other stiffening means. The subsequent detailed description of it will describe it as a floor covering, although it is obvious that the material may be used in the manufacture of wall displays. The same treatment which makes the board lie fla-t also helps keep foot marks from soiling the display material.

I have found that by forming a continuous pattern of :alternate small elevations and shallow depressions which divide the sheet into a plurality of small areas, the fiber of the board is so broken up that its tendency to curl in either dimension is destroyed. Preferably the pattern is made by 'forming two sets of intersecting crease score lines in the sheet so as to give a sort of waffle or checkerboard pattern. This operation may conveniently `be performed by a process which forms score lines alternately on opposite sides of the sheet, so that each score line on one side is halfway between a pair of score lines on the other side; and each surface thus has alternate elevations and depressions with each elevation in one side having a complementary depression in the other side. This opera-tion is performed twice in 'preparing a paperboard sheet for use as a iioor covering, so as to break u-p the grain of the sheet in both directions. The wallie scoring of the 'surface gives the sheet some non-skid properties; and the small elevation in the sheet opposite each score line makes it slightly springy, or soft underfoot.

The operation is performed by passing the paperboard between rollers, or between a roller and a flat plate, which have meshing teeth so spaced that the paperboard is first bent slightly by the meshing teeth, and is gradually bent more sharply until it is gripped by the teeth. No two adjacent parts of the sheet are ever gripped by the teeth at the same time, so that the sheet is sharply bent sequentially along closely spaced lines which extend entirely across the sheet in one direction. The successive manipulation of parallel strips permits foreshortening of the sheet without tearing it, and results in a board which has its grain broken continuously at closely spaced intervals, but in which the grain is not torn or ruptured.

A principal use of the improved sh-eet material is in display advertising, as it permits .the production of a floor mat display which will stand up for a substantial period of time under the ordinary traffic in a neighborhood grocery store, drug store, or the like. Preferably the sheet is prepared with a complete design or advertising display on each of its surfaces so that it may be used twice.

The invention is illustrated in a preferred embodiment in the accompanying drawings, where- 1n:

Fig. 1 is a plan view of a sheet of paperboard in Iaccordance with the invention;

Fig. 2 is an elevation of one edge thereof;

Fig. 3 is an elevation of an edge adjacent the edge shown in Fig. 2

Fig. 4 is an enlarged fragmentary bottom plan viev of one corner of the sheet shown in Fig. l; an

Fig. 5 is an enlarged fragmentary elevation of the edge shown in Fig. 3.

Referring to the drawings in greater detail, and referring particularly to Fig. 5, the improved sheet material is composed of a laminated paperboard body I0 which maybe from 30 to 75 thousandths of an inch thick and which is formed of a plurality of` individual laminae i l. In order to make a floor covering or display door mat -which will withstand ordinary washing and cleaning operations, the laminat-ed paperboard I0 should be impregnated with a waterproofing compound, and the preferred compound is a melamine resin.

Bonded to each surface of the laminated body I0 is a paper facing l2, the bonding material preferably being a Waterproof adhesive so that the complete composite sheet will substantially resist disintegration when wet.

The paper facings may be either coated or uncoated paper, depending upon `whether the finished composite sheet is to have a sharp brilliant color such as is obtained by applying the color to a coated sheet, or whether it is to have the more subdued color which is obtained by applying it -to an uncoated sheet so that it penetrates the ber paper. Preferably, the paper facings may be printed o1' lithographed with any desired decorative design or advertising material in the ways which are conventional for the manufacture of display advertising cards.

The `composite sheet with the desired decorative design or advertising display matter reproduced thereon is then provided with an adherent waterproof nlm which covers -eac'h of its surfaces. This is preferably accomplished by applyingtwo or three thin coats of transparent waterproofy lacquer; although it is alain that for certain uses,

such as automobile ilo-or mats, the coating need not be transparent.

The waterproofed composite sheet is'then subjected to a crease scoring operation in order to divide it into a plurality of polygonal areas, each of which must be of such small dimension that no signicant warping strains may occur within it. Thus, by dividing the entire sheet into such small area, the warping tendency of the whole sheet is substantially abolished. The scoring operation is performed as previously stated herein. When the scoring operation has been performed according to the preferred method, the sheet has a plurality of straight parallel crease score lines i3 running continuously across it in one direction, with the score lines i3 in one surface alternating with those in the other surface. After the score lines i3 have been formed in the sheet it presents a flat, iiuted appearance.

The composite sheet is then subjected to a second scoring operation Ito form score lines le at right angles to the score lines i3. These are also parallel, continuous straight score lines; but as will be noted by comparison of Figs; 2 and 3, the score lines it are of less depth than the score lines I3. The reason for this is that if the second set of score lines is placed in the sheet at the same pressure as the irst set, it partially destroys the first score lines where the intersections occur.

The nished sheet is 'thus divided into a plurality of .squareareas l so that the finished sheet presents a patterned appearance which may be described as waile like, checkerooard or quilted As best seen in Fig. 4 each of the squares I5 is a small elevation bordered by shallow depressions, with the apex of the elevation in one face of the sheet occurring directly opposite the score line in the other face of the sheet. Due to the difference in pressure used in forming the score lines i3, and Ill the convexity parallel to the score lines I3 is much more pronounced than is that parallel to the score lines i4.

If the material is to be used as a iioor covering, or for a floor mat display, it may be provided with fastening or anchoring means by which it' may be secured to the floor. Preferably a finished sheet carries a decorative design or display material on each of its surfaces so that when one surface has become unsightly from use, the sheet may be reversed and the second side exposed. Accordingly, the preferred fastening means comprises small sponge rubber strips l5 which are about 11s thick, and are provided with a coating of pressure sensitive adhesive i'l von eachv face.

Thus, the strips IB may readily be adhered to either surface of a display device formed from the improved board, and serve to secure the device to the floor. When it is vdesired. to turn 'the device over, the adhesive strips may be removed from one face and placed upon the other face so as to be reused.

The above and foregoing detailed description is given rfor clearness of understanding only and no unnecessary limitations should be understood therefrom, as variations will be apparent to those skilled' in the art.

I claim:

1. A decorative paperboard floor mat, comprising: a laminar paperboard body impregnated with a melamine resin; a lithograph-ed paper facing bonded over its entire area to each surface of said paperboard body with waterproof adhesive to form a composite sheet; and an adherent transparent, waterproof film on each facing; said sheet havingr at least two separate series of parallel, straight, crease score lines which are alternately on opposite faces of the sheet, said series being aligned in at least two `directions to fo'in alternate ooncavities and convexities which divide the sheet into a plurality of polygonal areas within which no significant warping strains may occur, whereby said sheet is substantially planar and has undulations over its entire surface which are of very low neig-ht in proportion to their breadth, and is substantially 'serp-proof.

A floor mat according to claim l wherein there are only two series of score lines which run substantially at right angles to one another.

3. A, floor mat according to claim 2 wherein the two series of score lines are formed in the sheet serially, and the second series is of less depth than the first series.

a. A laminar paperboard sheet material which is generallyv planar and has a continuous pattern of crease score lines alternately on opposite faces over its entire area which render it slightly undulatory in cross section as viewed along any plane perpendicular to the plane of the sheet so that it is divided into a plurality of small areas within which no signicant warping strains may occur, whereby the material is substantially Warp-proof.

5. A laminar paperboard sheet material which has been subjected to progressive spaced crease scoring of its entire area in at least two directions, the scores in any one direction being alternately on opposite faces of the sheet, so that said material is generally planar and has low vundulations which run continuously in said two .directions to divide the material into a plurality of small areas within which no signicant warping strains may occur, whereby said material is substantially warp-proof.

6. The material of claim 5 wherein the material is provided with. a first series of parallel crease scores and is thereafter provided with a second series of parallelv crease scores which are perpendicular to .said rst series.

7. The material of claim 5 in which the second series ofcrease scores is shallower than the first series.

8. A laminar. paperboard sheet material which has a succession of spaced parallel crease score lines extending entirely across it in at least two different directions to divide it into a plurality of small areas within which no signicant warping strains may occur so that it is substantially warp-proof, the crease score lines which extend in any one direction being alternately on opposite faces of the sheet, whereby said material is generally planar and has substantially regular undulations of small size over its entire area in said two directions.

9. A laminar paperboard sheet material which has a continuous pattern or breaks in its bers in at least two directions Which divide it into a plurality of small areas of unbroken ber within which no significant warping strains may occur, whereby the material is substantially warp-proof, said material being substantially planar, of substantially uniform thickness, and having a continuous pattern of small elevations and shallow depressions over its entire area.

10. A laminar paperboard sheet material which has been manipulated by sharply bending it sequentially along closely spaced lines which extend entirely across its area in one direction, and thereafter sharply bending it sequentially along closely spaced lines which extend entirely across its area substantially perpendicular to said first lines, so that there is a pattern of broken fibers extending across the sheet in two directions which divide it into a plurality of small areas of unn broken fiber within which no signicant warping strains may occur, whereby the material is sub stantially warp-proof, said material being sub- 6 stantially planar and having a continuous pattern of small elevations and shallow depressions over its entire area.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 65,904 Griffen June 18, 1867 81,199 Ott Aug. 18, 1868 969,460 Chartener Sept. 6, 1910 1,409,768 Perry Mar. 14, 1922 1,611,330 Bird Dec. 21, 1926 1,808,590 Andernach June 2, 1931 1,887,200 Hand Nov. 8, 1932 2,030,135 Carpenter Feb. 11, 1938` 2,032,114 Clements et al Feb. 25, 1936 2,075,386 Woodford Mar. 30, 1937 2,216,803 Benda Oct. 8, 1940 2,233,592 Dunajeff Mar. 4, 1941 2,268,477 Elmendorf Dec. 30, 1941 2,459,364 Charles et al. Jan. 18, 1949 FOREIGN PATENTS Number Country Date 8,334 Great Britain 1893 

10. A LAMINAR PAPERBOARD SHEET MATERIAL WHICH HAS BEEN MANIPULATED BY SHARPLY BENDING IT SEQUENTIALLY ALONG CLOSELY SPACED LINES WHICH EXTEND ENTIRELY ACROSS ITS UREA IN ONE DIRECTION, AND THEREAFTER SHARPLY BENDING IT SEQUENTIALLY ALONG CLOSELY SPACED LINES WHICH EXTEND ENTIRELY ACROSS ITS AREA SUBSTANTIALLY PERPENDICULAR TO SAID FIRST LINES, SO THAT THERE IS A PATTERN OF BROKEN FIBERS EXTENDING ACROSS THE SHEET IN TWO DIRECTIONS WHICH DIVIDE IT INTO A PLURALITY OF SMALL AREAS OF UNBROKEN FIBER WITHIN WHICH NO SIGNIFICANT WARPING STRAINS MAY OCCUR, WHEREBY THE MATERIAL IS SUBSTANTIALLY WARP-PROOF, SAID MATERIAL BEING SUBSTANTIALLY PLANAR AND HAVING A CONTINUOUS PATTERN OF SMALL ELEVATIONS AND SHALLOW DEPRESSIONS OVER ITS ENTIRE AREA. 